According to IAS 21, the Preferred Treatment for Recognizing Gains

According to IAS 21, the preferred treatment for recognizing gains and losses on foreign currency transactions

A) is similar to the way U.S. tax accounting treats gains and losses.
B) is to recognize differences as income or expense in the period in which they arise.
C) follows the German approach of conservatism.
D) is to recognize losses but not gains in the period in which they arise.